Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 1591:

  Which of the following is a physical change?

  Options:
  A) Exposing white phosphorus to air
  B) Burning kerosene
  C) Dissolving calcium in water
  D) Freezing ice cream
  Show Answer
  The correct answer is D .
• Question 1592: Addition of an aqueous solution of a salt gives a white precipitate. The salt is likely to be a? Options:
  A) nitrate
  B) carbonate
  C) chloride
  D) sulphide
  Show Answer
  The correct answer is B .
• Question 1593: Deliquescent substances are also? Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 1594: The acid anhydride that will produce weak acid in water is Options:
  A) SO₃
  B) NO₂
  C) SO₂
  D) CO₂
  Show Answer
  The correct answer is D .
• Question 1595: Cancerous growths are cured by exposure to Options:
  A) γ - rays
  B) β - rays
  C) α - rays
  D) x - ray
  Show Answer
  The correct answer is D .
• Question 1596:

  

  The IUPAC name for

  Options:
  A) 1-methlpentane
  B) 3-methylbutane
  C) 2-methylbutane
  D) 1-dimethylpropane
  E) 2-methylpentane
  Show Answer
  The correct answer is C .
• Question 1597: N₂O_4(g) ↔ 2NO_2(g). Increase in total pressure of the equilibrium reaction above will Options:
  A) produce more of NO_2(g) in the mixture
  B) convert all of N₂O_4(g) to NO_2(g)
  C) have no effect on the concentrations of NO_2(g)and N₂O_4(g)
  D) produce more of N₂O_4(g) in the mixture
  Show Answer
  The correct answer is D .
• Question 1598: The hydrocarbon used in the production of styrene is Options:
  A) ethyne
  B) propyne
  C) ethane
  D) ethene
  Show Answer
  The correct answer is D .
• Question 1599:

  The shapes of water, ammonia, carbon (iv) oxide and methane are respectively

  Options:
  A) linear, tetrahedral, angular and pyramidal
  B) angular, pyramidal, linear and tetrahedral
  C) pyramidal, linear, tetrahedral and angular
  D) tetrahedral, angular, pyramidal and linear
  Show Answer
  The correct answer is B .
• Question 1600:

  In the preparation of oxygen by heating KCIO, in the presence of MnO${}_2$ only moderate heat is needed because the catalyst acts by ${}_2$

  Options:
  A) lowering the pressure of the reaction
  B) increasing the surface area of the reaction
  C) increasing the rate of the reaction
  D) lowering the energy barrier of the reaction
  Show Answer
  The correct answer is D .